BARCELONA, SPAIN - MARCH 11: Catalan Autonomous riot police officers stand guard at the first Pegida rally on March 11, 2015 in Barcelona, Spain. Pegida Catalonia has called for the first Pegida Spain march in on the 11th anniversary of the 2004 Madrid train bombings. (Photo by David Ramos/Getty Images)
(2015 Getty Images)

MADRID (AP) – Spanish police say they have arrested 56 men in a nationwide operation against internet child pornography.

A police statement Thursday said the detainees are suspected of distributing abusive images involving children on peer-to-peer internet file-sharing sites. Those arrested were mostly Spaniards, aged between 40 and 60.

It said officers seized some 170 hard discs and 600 CDs and DVDs containing child pornographic material in nearly 40 house raids.

Police said the arrests took place over several months in provinces across Spain.

The statement said the operation was the result of an 18-month investigation.